"No permit has been issued to anybody for any activities at Pier 1 or on the adjacent shoreline," said Larry Goldzband, executive director of the San Francisco Bay Conservation and Development Commission. "We have started an enforcement action with regard to activities at the pier and shoreline."

The directive comes after numerous complaints about the construction since the spring when it came to light that Google was building a floating structure at the island.

The barge, made of 80 stacked shipping containers, will have to be moved to another permitted facility in San Francisco Bay while the authority seeks a Conservation and Development Commission authorization to moor the craft on Treasure Island, Goldzband said. The authority could face fines or enforcement proceedings if it doesn't comply.

"The enforcement action would go away if the barge is moved to a properly permitted facility," he said. "There are a number of them throughout the bay. We have offered to work with them to find a properly permitted place."

Google's response to the order did not shed much light on the Internet giant's plans.

"We just received the letter from the San Francisco Bay Conservation and Development Commission and we are reviewing it," a Google representative wrote in an e-mail.

Criticism around the Bay Area and on the Web sprung up when the secret project was revealed. The builder, Turner Construction Co., told The Chronicle that Google was building three vessels at a cost of $35 million that would eventually be docked in San Francisco, Los Angeles and New York.

Google has been vague about its plans, prompting speculation from contractors and others that the company was building a floating computer eyewear store or a data storage center or was planning to use the barge as a party boat.

Preliminary plans submitted to the Port of San Francisco showed plans for a "studio" and "temporary technology exhibit space." Google officials said that although things may change, the plan now is for the barge to be "an interactive space where people can learn about new technology."

The order delays construction at least through the winter, which Goldzband said was already happening. Once construction is finished, he said, Google will need to get its own permits from the Conservation and Development Commission if it plans to moor the barge in the bay.